In the field of high precision micromechanics, and that of clockwork in particular, it is well known to use so-called shock-resistant devices to protect components, for example, those of a watch. Such devices, for example, consist of shock-resistant bearings or shock-resistant clamps as described in documents CH 700,496; EP 1,696,286; EP 2,629,160; EP 1,975,749; or CH 701,549, for example.
Documents CH 700,496 describes a shock-resistant bearing for a clockwork part comprising a body, a bearing mounted in the body and having a hole able to receive a pivot, elastic means acting axially on the bearing and guide means for forcing the bearing to move only axially against the axial action exerted by the elastic means during a radial movement of the pivot. Said guidance and elastic means consist of pre-stressed elastic blades. These blades are more rigid radially than axially, such that the bearing moves almost entirely axially, even upon radial shocks.
Although this type of device makes it possible to protect the pivot from shocks, it does not absorb the kinetic energy from the shock, such that said energy is transmitted to the rest of the movement, which may be damaged.
Document EP 1,696,286 describes a shock-resistance bearing for a timepiece, and more particularly for a pivot-shank of a staff of a wheel of a timepiece, comprising a support block designed to be driven, fixed or formed in the frame of said timepiece, said support block being provided with a housing provided to receive a setting supporting a pierced stone crossed through by the pivot-shank and an end-stone. The setting is kept in the housing using a spring with axial and radial deformation that is formed by a rigid peripheral ring forcibly mounted against the wall of the housing while bearing on a bead situated at the bottom of the housing so as to arrange a space allowing a certain axial travel of the spring, a substantially annular rigid central support and elastic means connecting said peripheral ring to said central support. Secondarily, the space between the arms of the spring can be filled with a “shock-absorber” substance, such as a polymer, for example.
This type of shock-absorber bearing, although acting elastically both in-plane and outside the plane without requiring an intermediate part, has the drawback of only having an elastic response to a shock. Thus, the kinetic energy of the shock is not absorbed and can spread to the rest of the movement, at the risk of damaging it. It will be noted that in the alternative embodiment in which the space between the arms of the spring is filled with a shock-absorbing polymer, there is no free space for the blades to be able to bend and the radial shocks are therefore not absorbed, yet the radial shocks are much more frequent than out-of-plane shocks.
Document EP 2,629,160 describes a shock-absorber including a lateral buffer element positioned between a bracelet watch case and a watch module, in which the lateral buffer element comprises a plurality of buffer layers respectively having different transmissibilities of the vibrations for predetermined frequencies. Thus, when the bracelet watch case is subject to vibrations due to external shocks, the different buffer layers of the lateral buffer element attenuate and absorb the low-frequency and high-frequency vibrations, respectively.
Document EP 1,975,749 describes a timepiece whereof the movement is held elastically. Said timepiece comprises a case, a movement, an elastic shock-absorber organ holding the movement inside the case and a manual control organ crossing through a wall of the case and connected to the movement, said timepiece further comprising a rigid tube crossing through said wall, in which tube the manual control organ is engaged, and an elastic shock-absorber sleeve interposed between the tube and said wall. The elastic shock-absorber sleeve is formed in a single piece with the elastic shock-absorber organ that surrounds the movement, the latter being made from rubber.
These two types of device have the drawback of not keeping the movement in place precisely in the case, not procuring correct repositioning of the movement after the shock and not protecting the movement against axial shocks.
Document CH 701,549 describes an anti-shock watch including shock absorbers to mount the watch movement inside the case. Each shock absorber includes a plurality of independent portions suitable for absorbing the energy of the shocks and vibrations in different portions of the frequency spectrum, a first shock-absorber portion being made from metal and another portion of the same shock absorber being made from a softer material, such as a synthetic, rubber, colloid or gel material, for example.
Although this type of device makes it possible to filter both low and high frequencies, and to allow repositioning of the movement using flanges, it nevertheless has the drawback of being particularly cumbersome.
Yet the latest technological advances in the field of high precision micromechanics, and more particularly the field of timepieces, increasingly frequently use silicon, which, although having many advantages, such as showing no fatigue, being nonmagnetic, or allowing the serial production of parts with high precision while offering a high design freedom, nevertheless still has the drawback of being fragile and breaking, such that it does not withstand accidental shocks very well. Such silicon timepieces are in particular described in documents EP 1,422,436; EP 2,105,806; and EP 1,736,838.
Document EP 1,422,436 describes a balance-spring designed to equip the balance of a mechanical timepiece and provided with a spiral bar obtained from monocrystalline silicon.
Document EP 2,105,806 describes an escapement mechanism arranged to transmit pulses of mechanical energy from a motor source to an oscillating regulator of a timepiece by means of a strip-spring working by buckling around an inflection point, said strip-spring being able to accumulate the energy from the motor source between two pulses and transmit it to the oscillating regulator upon each pulse by levers. The strip-spring is mounted on a chassis and said strip-spring and/or said chassis is made from silicon, with or without being in a single piece.
Document EP 1,736,838 describes a mechanical oscillator including a system of flexible articulations mounted around a virtual pivot, capable of significantly increasing the power reserve of the watch.
The shock absorbers of the prior art are not suitable for this type of system, yet they are particularly sensitive to shocks and/or vibrations, even more so given that this type of system is usually manufactured from silicon.
There is therefore a need for an anti-shock device able to absorb shocks and/or vibrations in all directions, and more particularly the radial and axial directions, to dissipate all or part of the kinetic energy caused by the shocks and to be integrated into different locations of a timepiece, in order to avoid any deterioration of the parts of the watch, and more particularly the parts made from silicon, which is fragile and breakable, such as flexible guide mechanisms, for example.